Impact of Indian Ocean Dipole on high-frequency atmospheric variability over the Indian Ocean

A strong relationship between Indian Ocean Dipole (IOD) and high-frequency (HF) atmospheric variability in the low-level zonal wind is reported in the present study. We found that the HF atmospheric variability over the Indian Ocean (IO) is strongly modulated by IOD events, that is, HF atmospheric variability becoming significantly energetic during negative IOD events. This relation still holds even after the ENSO effect is statistically removed. Our results suggest that the HF atmospheric variability is state-dependent on the IOD coupled system. Furthermore, it is demonstrated that there is a significant decadal change in this dependence. That is, the dependency of HF atmospheric activity on the IOD phase has become stronger in the recent decade. (C) 2008 Elsevier B.V. All rights reserved.